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The liquidus lines of binary systems of dibasic carboxylic acids HOOC–(CH2)n–COOH (n = 3, 4, 7, 8) and eutectic coordinates were calculated by the Schrӧder–Le Chatelier equation. The experimental studies were performed by differential thermal analysis on a DSC heat flux microcalorimeter. Five or six mixtures with different contents of components were studied in each system. The phase diagrams were constructed based on the set of DSC data. The experimental melting temperatures and the composition of binary eutectics were compared with the calculated values. All the systems were of the eutectic type. A theoretical analysis of the solubility of the acids was performed, and the equations of solubility of acids in water were obtained. The eutectic composition of the pentanedioic–hexanedioic acids system was chosen based on the analysis of the solubility data; it can be used to obtain anodic coatings on aluminum. For the eutectics of the system, the solubility in water was experimentally studied at temperatures from 20 to 60°C. The composition of electrolyte for aluminum anodization was developed: eutectic mixture of pentadioic and hexanedioic acids, ethanedioic acid, and water. The temperature and time of aluminum anodization were recommended.

A possibility to use acid-type phosphoryl-containing podands with diethylene glycol polyether chain, which differ in substituent at the phosphoryl group, as extractants for the recovery of U(VI), Th(IV), and rare earth elements(III) from nitric acid solutions has been studied. Features of the effect of HNO3 concentration on U(VI) and Th(IV) extraction with solutions of the phosphoryl-containing podands in dichloroethane has been revealed. Uranium(VI) is extracted as a normal intracomplex salt of dibasic acid UO2L3 with chelate coordination of both POO− groups to one cation. Thorium(IV) produces a complex as a normal intracomplex salt of composition Th(L3)2 where two bivalent anions of ligand acid are coordinated via all four POO− groups to Th(IV) cation. Sorption of U(VI), Th(IV), and REE(III) by impregnated sorbent based on LPS-500 polymer with 1,5-bis[2-(oxyethoxyphosphoryl-4-ethyl)phenoxy]-3-oxapentane from 0.052 and 3.52 mol/L HNO3 has been studied. It has been established that the obtained sorbent shows high selectivity in the separation of U(VI), Th(IV), and REE(III). The separation factor for uranium(VI) and europium(III) (βU/Eu) has been found to be 202 and ∼55000 upon sorption from 3.52 and 0.052 mol/L HNO3, respectively, at V/m = 500 mL/g. At thorium(IV) sorption from 3.52 and 0.052 mol/L HNO3, βTh/U = 66 and ∼5050, respectively.

Dissociation and complexation with Cu(II) cation is studied for phosphoryl-containing podands (tetrabasic 1,5-bis[2-(dioxyphosphoryl)-4-ethylphenoxy]acidic-type-3-oxapentane (H4LP) and dibasic 1,5-bis[2-(oxyethoxyphosphoryl)-4-ethylphenoxy]-pentane (H2LP)) and their carbonyl analog (polyether dibasic acid 1,5-bis[2-(oxycarbonylphenoxy)]oxapentane (H2LC) in water in the presence of 5% dimethylformamide potentiometrically, spectrophotometrically, and conductometrically. Phosphoryl podands exhibit good complexing properties and can selectively bind metal cations. The dissociation constants are determined and the distribution diagram of ionized species of the compounds under study depending on pH is plotted. The molar ratio between the metal and podand in all complexes is found to be 1 : 1. The stability constants of complexes with Cu2+ cation are calculated. The most stable copper(II) complexes are formed with the tetrabasic podand.

Phase equilibria in a three-component system composed of dibasic acids (hexanedioic, pentanedioic and nonanedioic) are investigated by means of differential thermal analysis. The eutectic composition is determined: 48.0 wt % pentanedioic acid, 20.0 wt % hexanedioic acid, and 32.0% nonanedioic acid. The melting temperature of the alloy is 70°C. It is concluded that this eutectic composition can be used to prepare electrolyte for thin-layer anodization.

DSC is used to measure the thermal effects of processes in mixtures of solid organic dibasic acids with powdered aluminum, subjected to plastic deformation under pressures in the range of 0.5–4.0 GPa using an anvil-type high-pressure setup. Analysis of thermograms obtained for the samples after plastic deformation suggests a correlation between the exothermal peaks observed around the temperatures of degradation of the acids and the thermally induced chemical reactions between products of acid degradation and freshly formed surfaces of aluminum particles. The release of heat in the mixtures begins at 30–40°C. The thermal effects in the mixtures of different acids change according to the order of acid reactivity in solutions. The extreme baric dependences of enthalpies of thermal effects are associated with the rearrangement of the electron subsystem of aluminum upon plastic deformation at high pressures.

Specific features of complexation in solutions of a strong dibasic acid in the H2SO4–2-pyrrolidone (Pyr) system (in the range of compositions of 0–100% H2SO4) are studied using multiple frustrated total internal reflection IR spectroscopy. The conclusions drawn on the structure of the complexes formed in such solutions are confirmed by quantum-chemical calculations of the mPyr · nH2SO4 (m, n = 1, 2) heteroassociates and by comparison of their calculated and measured vibrational spectra. It is found that, in the investigated solutions, four types of acid–base complexes, with various degrees of proton transfer in the OHO bridge, are formed: (AHA)– anions with quasi-symmetric H-bonds, solvated by acid molecules, or entering into the composition of PyrH+ · (AHA)– ion pairs; quasi-ion pairs with incomplete proton transfer to the base molecule of 1: 1 and 2: 2 compositions; and 2Pyr · H2SO4 complexes with two O–H···O bridges of molecular type. The main differences in the mechanisms of the acid–base interactions in the H2SO4–Pyr system as compared to the CH3SO3H–Pyr system result from the participation of two OH-groups of H2SO4 molecule in these interactions. Therefore, two types of quasi-ion pairs and complexes of 2Pyr · H2SO4 composition are formed.

For the first time it has been experimentally shown that a powder of detonation nanodiamonds (DND) and a saturated acyclic hydrocarbon, mono- or dibasic alcohol, used as the reaction mixture after treatment at high pressures (5–8 GPa) and high temperatures (1300–1800°C) results in the formation of diamond single crystals up to 15 micron in size. The Raman spectrum indicates that the diamonds have a perfect of crystal structure. It has been suggested that the oriented attachment mechanism is responsible for growth of micrometer-size diamond single crystals out of DND particles with sizes of about 5 nm under these technological conditions.

The Ritter reaction of dibasic carboxylic acids of the adamantane series with carboxy and carboxymethyl groups attached to bridgehead carbon atoms afforded a number of amino polycarboxylic acids.

A series of copolyimides were prepared by thermal imidization of polyamide acids derived from 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 2,3′,3,4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, p-phenylenediamine and 4,4′-oxydialinine commonly used for the production of commercial polyimides. The flexible copolyimide films characterized by ultra-low coefficient of thermal expansion were obtained and characterized by FTIR, WAXD, TG, DMA, TMA, FE-SEM and tensile properties measurement. The results showed that three copolyimides remained semi-crystalline and exhibited high glass transition temperature, high thermal stability, and great ultimate strength.

The catalytic properties of zeolites HY, HBeta, and HZSM-12 and of mesoporous amorphous aluminosilicate in liquid-phase esterification of aliphatic (monobasic C1–C18, dibasic C6, C10) and aromatic (benzoic, trimellitic, phthalic) carboxylic acids with butanol were studied. Zeolite HBeta appeared to be the most active catalyst. Procedures were developed for preparing esters in the presence of zeolitic catalyst HBeta, ensuring 100% selectivity of ester formation at 90–98% conversion of the acid.

The method for phoreograms processing using the least squares method, taking into account the water conductivity and carbon dioxide content was developed. Thus we reduced the threshold concentration of test solutions to 10−6 M. The method was used in processing the results of measurements of conductivity of aqueous solutions of a number of phenols and dibasic organic acids.

The stability constants of 1: 1 and 1: 2 acidic copper(II) violurate complexes and the CuL complex, where L is the anion of violuric acid (H2L), were determined by pH-metry at ionic strength I = 0.1 at 20°C. The stability of the violurate complexes of triply charged cations [ML]+ and quadruply charged thorium [ThL]2+ increases in the sequence La3+, Gd3+, Y3+, Sc3+, Th4+, Fe3+. It was shown that violuric acid behaves as either mono- or dibasic, depending on the conditions, with respect to all of these cations.

A procedure for the purification of aqueous glyoxal (obtained by the partial oxidation of glycol) from carboxylic acids was described. Mono- and dibasic organic acids can be removed from solution without any substantial losses of glyoxal by using weakly basic EDE-10P and AN-31 anionites. A mechanism of the adsorption of carboxylic acids on weak resins was suggested based on the IR spectra recorded in a study of AN-31 anion-exchange resin. Using this method of purification also allowed the removal of the glyoxal condensation products from solution.

Amino acids are polyfunctional reagents allowing target-oriented synthesis of various heterocyclic structures. The reaction of cysteine with levulinic acid gives a dibasic acid which readily loses water at elevated temperature, yielding bicyclothiazinone [1]. In the reaction of cysteine with 5-methylfuran-2(3H)-one, the amino acid initially adds to the double bond in the furan ring, and opening of the latter and subsequent dehydration lead to heterocyclic compound. The product is stabilized via further dehydration with formation of 5-oxothiazolidinecarboxylic acid [2]. The reaction of furan-2(3H)-one with L-cysteine involves initial attack by the amino group on the carbonyl carbon atom to produce oxo acid amide which is converted in solution into bicyclic hexahydropyrrolothiazole structure [3, 4]. Levulinic and β-benzoylpropionic acids were reported to react with anthranilic acid on heating in dichlorobenzene to produce 3a-methyland 3a-phenyl3,3a-dihydro-5H-benzo[d]pyrrolo[1,2-b][1,3]oxazine1,5(2H)-diones, respectively [5, 6]. In the reactions of anthranilic acid amide with levulinic and β-benzoylpropionic acids on heating in chlorobenzene 3a-methyland 3a-phenyl-2,3,3a,4-tetrahydropyrrolo[1,2-a]quinazoline-1,6-diones were obtained, respectively. Binucleophilic α-amino acids (cysteine, penicillamine, serine, and threonine) were studied in reactions

The coordination properties of zinc 5,15-di(ortho-aminophenyl)octaalkylporphyrin in reactions with mono- and dibasic nitrogen bases in benzene are studied by means of computational modeling and spectrophotometric titration. The stability of molecular zinc porphyrinate complexes in solution is estimated and their structure is determined. The correlation between the coordination properties of the compound under investigation and electronic and conformational factors of the macrocycle is established. The base nature is shown to affect the stability of zinc porphyrinate complexes. The correlations between the calculated σ bond energy of the zinc atom with the nitrogen atom of the base (E b) and the equilibrium constant of the axial coordination reaction are obtained. It is demonstrated that the reaction is accompanied by an increase in steric hindrance and a change in the type of deformation of the porphyrin ligand.

1. In the national pulse MHD generators with power from 10 to 600 MW, solid plasmagenerating propellants (SPPs) are used, which contain dibasic ballistite powders with an aluminum content of up to 21% (in mass) and an easily ionized seed like cesium or potassium nitrates (1-3). New SPPs should have increased values of the energy complex σv 2 (σ is the electrical conductivity, and v is the velocity) and the heat content of combustion products, which depends on their heat capacitance at constant pressure and the calorific power of the fuel. The value of the complex σv 2 depends mainly on temperature, while the heat capacitance is related to the combustionproduct composition and their degree of dissociation, which depends on the oxidizer excess factor α. The prelimi� nary study of new SPP compositions shows the possi� bility of a substantial increase in both the complex σv 2 and the coefficient α.

Equilibria in binary and ternary systems containing cobalt(II) and nickel(II) salts, nitrilotriacetic acid, and dicarboxylates were studied by spectrophotometry with NaClO 4 as a supporting electrolyte (I = 0.1) at T = 20 ± 2°C. The molar and proton compositions of the complexes and the pH ranges of their existence were determined. The stability constants of the homo- and heteroleptic complexes were calculated. The pH-distribution of the detected complexes was obtained. The experimental data were processed in terms of the mathematical models that predict the existence of a wide spectrum of complex species in solution and allow ignoring those species that are negligible for accurate reproduction of the observed pattern.

New complexes of a Schiff base derived from 2-hydroxy-5-chloroacetophenone and glycine with Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and UO2(VI) have been synthesized. The ligand and the complexes have been characterized on the basis of analytical data, electrical conductance, IR, ESR, and electronic spectra, magnetic susceptibility measurements and thermogravimetric analysis. The ligand acts as a dibasic tridentate (ONO) donor molecule in all the complexes except the Zn(II) complex, where it acts as a monobasic bidentate (OO) donor. Antibacterial activities of the ligand and its metal complexes have been determined by screening the compounds against various Gram(+) and Gram(−) bacterial strains. The solid state d.c. electrical conductivity of the ligand and its complexes has been measured over 313–398 K and the complexes were found to be of semiconducting nature.

The method suggested earlier by the authors was used to analyze the regularities of electrolytic dissociation processes for weak dibasic and tribasic organic acids participating in the tricarboxylic acid cycle (Krebs cycle), most important biochemical process that completes the oxidation of main intermediates of degradation of hydrocarbons, fats, and proteins in a living body. The dissociation degrees, concentrations of ionized and nonionized forms in dilute (0.1–10 mM) solutions of oxaloacetic, citric, isocitric, α-keto-glutaric, succinic, L-malic, and fumaric acids were calculated.

Intermediate cerium(IV)-citrate complexes formed at the first stage of the oxidation of citric acid (Citr) with cerium(IV) were studied spectrophotometrically and pH-potentiometrically at ionic strength I = 2 (sulfate medium). Their composition and the form of the organic ligand present in them, the thermodynamic parameters of their formation, and the kinetic parameters of intramolecular redox decomposition were determined. A detailed scheme of the initial stages of the redox process in the Ce4+-SO 4 2− -Citr system was considered, and the law of its initial rate and intermediate mechanism were determined. The results were compared with the corresponding data on several oxycarboxylic acids and polyhydric alcohols. The inverse linear correlation was found between the logarithms of stability constants and the logarithms of rate constants for intramolecular redox decomposition of [(CeOH)H−2R]+ complexes with dibasic ligands of the type R = H2L, H(OH)L, and L(OH)2. The stabilizing role played by ligand oxy groups in these complexes was demonstrated.

Scientific principles of the manufacture of high-strength heat-resistant polymer composite materials with the successive ionizing-radiation and heat treatment (via the step of long-lived prepregs) were developed. Methods for the selection of components for the preparation of long-lived prepregs, as well as for the determination of the optimal curing conditions, were proposed. The mechanical properties of the materials were studied.

The synthesis of a new Schiff base derived from 2-hydroxy-5-chloroacetophenone and 4-amino-5-mercapto-3-methyl-1,2,4-triazole and its coordination compounds with Ti(III), VO(IV), Cr(III), Mn(III), Fe(III), Zr(IV), MoO2(VI), and UO2(VI) are described. The ligand and the complexes have been characterized on the basis of analytical, electrical conductance, molecular weight, IR and electronic spectra, magnetic susceptibility measurements, and thermogravimetric analysis. The ligand acts as a dibasic tridentate molecule. Antibacterial activities of the ligand and its metal complexes have been determined by screening the compounds against E. coli, S. typhi, P. aeruginosa, and S. aureus. The solid state de electrical conductivity of the ligand and its complexes have been measured over 313–403 K, and the complexes were found to be of semiconducting nature.

The ozonization of several model lignin compounds (guaiacol, 2,6-dimethoxyphenol, phenol, and vanillin) was studied in acid media in the presence of iron(III) ions. It was found that Fe3+ did not influence the initial rate of the reactions between model phenols and ozone but accelerated the oxidation of intermediate ozonolysis products. The metal concentration dependences of the total ozone consumption and effective rate constants of catalytic reaction stages were determined. Data on reactions in the presence of oxalic acid as a competing chelate ligand showed that complex formation with Fe3+ was the principal factor that accelerated the ozonolysis of model phenols at the stage of the oxidation of carboxylic dibasic acids and C2 aldehydes formed as intermediate products.

A series of phosphoryl compounds functionalized in the side chain were synthesized, and their membrane-transport properties with respect to proton-donor substrates of various acidity were studied. It was found that the efficiency of phase transport of the strong monobasic perchloric acid correlates with the basicity of the phosphoryl carriers in a series of carriers containing oxygen-containing functional groups. The transport flow sharply increases in going to phosphorylated amines, whereas phosphoramidates in their efficiency are closer to phosphonates than to amines. The efficiency of transport of dibasic acids (oxalic and tartaric) is low, since the hydroxy and carboxy groups not bound to the carrier make ionic associates highly hydrophilic. Fine details of the structure-transport acitivity relationship in the series of phosphorus compounds were discussed. Three-dimensional correlation analysis was used to compare the structure of the carriers with their characteristics: basicity of amine centers, atomic charges of oxygen and nitrogen, and hardness and hydrophobicity parameters.

The protolytic equilibria on the surface of silicas coated with a layer of maleinized linseed oil (MLO), a new type of carboxylic cation exchangers, were studied using potentiometric titration. The ionexchange capacity of the sorbents was determined, a parameter that first increases and then decreases with increasing concentration of MLO on the silica surface. For the dibasic carboxy groups of MLO, pKa=3.99±0.04 and 4.73±0.04, values close to pKa for succinic acid, a homogeneous analogue of the system under study.

The dismutation of arylene phosphorodiamidites derived from the simplest phenols and naphthols and of their dibasic analogs was studied. The main regular trends of this process and the limits of its synthetic applicability were determined.

The formation of surface defects in γ-Al2O3 obtained by pseudoboehmite calcination and plasticized with monobasic, dibasic, and tribasic organic acids is reported. The efficiency of catalysts in reforming reactions depends on the defectivity of the support.